Reversible self-priming pump



May 26, 1964 Filed April 19, 1963 c. F. HUBER 3,134,331

REVERSIBLE SELF-PRIMING PUMP 2 Sheets-Sheet 1 INVENTOR I 36 CHARLES F. HUBER ATTORNEY May 26, 1964 c. F. HUBER 3,134,331

REVERSIBLE SELF-PRIMING PUMP Filed April 19, 1963 2 Sheets-Sheet 2 INVENTOR CHARLES F. HUBER ATTORNEY coring.

United States Patent 3,134,331 REVERSIBLE SELF-PRINTING PUMP Charles F. Huber, Baltimore, Md., assignor to George '1. Adams, Baitimore County, Md. Filed Apr. 19, 1963, Ser. No. 274,257 9 Claims. (Cl. 1tl33) The present invention relates generally to the pumping of fluids and more particularly to an improved impeller to be used in a centrifugal or centripetal pump.

Rotary pumps of conventional design comprise a vaned rotary impeller within a stationary casing. In centrifugal pumps fluid enters at the center of rotation of the impeller and is driven up the vanes and out at their periphery through one or more tangential outlets in the casing. A

' centripetal pump functions by the reverse of this procedure; the fluid entering the casing at the periphery of the impeller and being forced down the guiding vanes and out at a central port.

At the present time, no pump has appeared on the market that is adaptable to both centrifugal and centripetal applications. Such a pump is highly desirable, but it has been found that the particular vane configuration designed to obtain a high head in a centrifugal pump produces high turbulence and consequent frictional losses in a centripetal pump While the impeller designed for centripetal use produces a similar undesirable effect in centrifugal applications.

Furthermore, eflicient pumps of either category, in the prior art, are either very expensive or very inefiicient.

The inexpensive pumps have impellers consisting of only a plate with a series of vanes thereon with the open side of the vanes lying adjacent the casing cavity wall. By designing a pump with this configuration, the impeller can be cheaply made by welding vanes on a stamped plate or by molding the impeller as a one-piece unit. Several disadvantages have been found in this arrangement. First, the fluid is rotated rapidly by the plate and vanes while a face of the fluid is in contact with the stationary casing cavity wall, causing large frictional losses and turbulence. This in turn causes cavitation and vane wear. Secondly, the placement of the moving vanes adjacent the casing cavity wall tends to induce fluid leakage over the vanes and the formation of a film between the vanes and the wall which reduces the designed tolerances and adds to the frictional losses.

Well-engineered and consequently, expensive pumps are designed with enclosed impellers which contain the fluid within the hollow interior of the impeller and use the casing only to direct the inlet and outlet of the fluid. Impellers of this type become expensive because of the fabrication problems arising due to the enclosed vanes within the chamber of the impeller. This unit can no longer be made of a one-piece casting without expensive If the impeller is fabricated from a pair of plates and vanes, jigs are required to provide the necessary alignment between the stub axles formed on each plate.

In both types of pumps discussed above, the vanes are the weak point. They tend to clog When the pump inlet is not properly filtered and the wear rate is surprisingly high, due to cavitation, when the fluid flow is large. Furthermore, the particular vane configurations present problems of fabrication over and above those of the impeller unit. While radial vanes can be used in a centrifugal or centripetal pump, these are not particularly efficient, especially in the centrifugal arrangement. Thus an eflicient pump design has required the utilization of volute or involute curves in the design of the vanes. While these curved vanes appear to be optimum at the present time, they still inherently present the problems of high friction and cavitation noted above.

Threfore it is an object of the present invention to pro- ICC.

vide an impeller that may be used efliciently in a pump for either centrifugal or centripetal applications.

Another object of the present invention is to provide an impeller which is inexpensive, while being more eflicient than the enclosed bodied impeller.

A further object of the present invention is to provide an impeller without expensive guiding vanes or difficultly fabricated components.

A still further object of the present invention is to provide a self-priming pump with the above advantages.

Other objects and advantages of the invention will be apparent from the accompanying drawings and description.

In the drawings:

FIG. 1 is a perspective view of the impeller of the instant invention;

FIG. 2 is a sectional view of the impeller assembled in a pump housing and taken along the line 2-2 of FIG- URE 3;

FIGURE 3 is a partial sectional view of the pump clearly showing the configulration of the impeller and its relation to the housing; and,

FIGURE 4 is a partial schematic representation of the pump driven by a reversible electric motor.

In the pump structure in FIGURES 1-3, the impeller is generally designated 19 and the pump housing is gen erally designated 12. The impeller consists of a pair of hollow abutting semi-circular sections generally designated as 14 and 14' offset equally on either side of the axis of rotation 16 and having centers at 17 and 17', respectively. These sections are proscribed by parallel plates 18 and 18' spaced apart by peripheral walls 20 and 20'. Since these walls 20 and 20' extend only across the semi-circular arcs of the sections 14 and 14' a pair of radially faced peripheral ports 22 and 22 are formed at the junction of the sections 14 and 14'. A stub axle 24, concentric with the center of rotation of the impeller 10 is mounted perpendicular to and extends outwardly from side plate 18. A concentric bore 26 extending a short distance into the stub axle 24 is provided with a keyway 26 on its inner periphery.

Coaxial with the stub axle 24, an axle 30 (FIG. 2) with a bore 32 is provided on side plate 18', said bore 32 extending through side plate 18' to connect with the hollow interior of the impeller 10.

The pump housing 12 (FIGS. 2 and 3) is formed by a main pump casing generally designated at 33 and a port cover generally designated at 34. The pump casing 33 comprises a base 36 supporting a circular, cup shaped impeller housing 38 and a concentric circular boss 40 mounted rearwardly thereof. The boss 40 has a concentric coaxial bore 42, the portion 44 thereof being adjacent the impeller casing and of enlarged cross sectional area to accommodate the stub axle 24. A grease seal 48 is fitted between the ball bearing 46 and the impeller body ltl while a second grease seal 50 is included in the smaller radius bore beyond the ball bearing 46. Drive shaft 52 extends into the bore 42 and is rotatably journalled in ball bearing 46. The stub axle of the impeller fits into the larger radius portion of the bore 42 and is mated with drive shaft 52 which nests in the coaxial bore 26. The impeller 10 is drivably connected to the above shaft 52 by key 54 which is in keyway 28. A radial passage 56 in the boss 40, between the grease seals, extends from the drive shaft 52 to the circumference of the boss where it is capped by a grease nipple 58.

The port cover plate 34 is bolted over the open end of the pump casing 33 by studs 60. The port cover plate 34 has a tubular boss 62 concentric with boss 40 and having an inner diameter large enough to rotatably support stub axle 30 by means of a soft metal bearing 64,- contained in the inner wall of the tubular boss 62. The outer end of 3 the tubular boss is internally threaded to accept a fluid tight fitting.

Turning to FIG. 3, it can be seen that the impeller body is concentrically mounted in the casing 33 of the housing 12 with a peripheral tangential port 66 in the periphery of the casing arranged tangential to the flow of fluid leaving the ports 22 and 22 of the impeller 10. The outer ends of the port forces 22 and 22 are formed with lips 68.

FIGURE 4 shows the pump 12, previously described, being driven by a reversible electric motor 70 by means of a schematic drive train '72.

In operation, the pump, when driven clockwise (as pictured in FIG. 3) provides a centripetal action which results in fluid entering through the peripheral tangential port 66 and being forced out of the axial port 74 connected to the tubular boss 62. When the motor 79 rotates the pump 12 in a counter-clockwise direction (as viewed in FIG. 3), the pump becomes a centrifugal one, fluid being drawn in axial port 74 and being driven out the tangential port 66.

The particular shape chosen for the impeller body imparts the desirable characteristics obtained. Whenlooking at the side view of the impeller, it is observed that a generally elliptical configuration is presented. This hecomes apparent when seen in light of the broken line '76 in FIGURE 3 which only serves to complete the basic outline of the approximated elliptical form, the main part of which is provided by the two offset semi-circular portions of the impeller. The shape has been utilized after observing a natural phenomenon called a devil twister, a tornado like formation native to the Southwest U.S.A. It has been found that contrary to the average persons belief, the wind currents in the devil twister do not have a circular motion, rather, an elliptical one. From this observation, I conceived the concept of a pump impeller which allows the fluid to assume a natural flow pattern similar to that observed in the devil twister. I have thus negated the need for flow guiding vanes or other restricting means in the flow path which inherently cause high turbulence and wear loss. Of course, by this arrangement the cost of manufacturing is materially reduced. The semi-circular shape of the impeller halves permits simpler machining and inspecting procedures than a curve of constantly changing radius such as one that is an involute vane.

Without the interior vane, the pump will work equally well as a centripetal pump, permitting the pump to be connected to a reversible electric motor to provide versatility, not previously possible.

The extended narrow lip shown at the tip of each port provides a sealing means for keeping fluid within its hemispherical area without causing a large frictional loss. Other wiper means may be included between the sides of the ports and the Walls of the casing if desired. With the closed impeller chamber in combination with the lips acting as sealing means, the pump will become self-priming, providing enough suction to initially draw the fluid into the pump.

While the foregoing has described the preferred embodiment of the instant invention, I have also discovered that certain modifications may be made therein without affecting the mode of operation or the principles upon which the invention is based. For example, I have discovered that one of the ports 22 or 22 may be sealed and an intermittent pump obtained. Also it is possible to make one of the semi-circular sections larger than the other by reducing the distance between axis 16 and center 17 or 17' and thereby obtain a pump which pumps or sucks on a varying cycle.

While the forms of apparatus herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise forms of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. In a fluid pump, a stationary casing enclosing a rotary im eller; said casing comprising an outer surface and an enclosed cylindrical central cavity, said cavity being defined by parallel, fiat end walls interconnected by a circular wall section having its axis perpendicular to said end walls; said impeller having an axis of rotation and comprising an outer surface and a hollow interior unitarily defined by a pair of spaced parallel planar side walls interconnected between their peripheries by a pair of guiding Wall sections perpendicular to the side Walls, each guiding wall sectionhaving contiguous, semicircular surfaces and straight terminal edges, said guiding wall sections being oifset from each other on opposite sides of the axis of rotation of the impeller so that one terminal edge of each guiding surface is further from the axis of rotation of the impeller than the other terminal edge of the same guiding surface, said planar side Walls and terminal edges defining a pair of peripheral ports; an axial port means interconnecting the hollow interior of said impeller with the outer surface of said casing and a tangential port extending through said casing tangent to the circular wall section of the cavity and interconnecting said cavity with the outer surface of said casing, 'said impeller being drivingly journalled in said central cavity in the casing with the axis of rotation of the impeller being coaxial with the axis of the circular wall section of the cylindrical cavity; the planar side walls of said impeller being parallel to the end walls of said casing cavity and adjacent thereto; the terminal edge of each guiding surface, furthest from the axis of rotation of the impeller, is adjacent the circular wall section of said casing cavity whereby a substantial amount of fluid may not pass between the planar side walls of said impeiler and the end walls of said casing cavity and between the further terminal edges of the guiding surfaces of said impeller and the circular wall section of said casing.

2. The fluid pump of claim 1 in which a radial lip is included at the radially outer edge of each peripheral port to provide a close tolerance fit between the impeller and the circular section of the casing cavity.

3. The fluid pump of claim 2 in which pairs of radial coplanar flanges extend in an axial direction from the outer surfaces of the planar side walls of the impeller adjacent the port areas to provide a close tolerance fit with the sides of the casing cavity.

4. In a pump motor combination, a rotary fluid impeller with an axis of rotation, said impeller having an outer surface and a hollow interior surface, said outer surface and said hollow interior both being defined by a pair of parallel planar side walls and a pair of semicircular guiding end wall surfaces extending therebetween, each guiding surface being offset on an opposite side of the axis of rotation of the impeller, said interior surfaces being the sole means for guiding fluid within said impeller, said impeller having an axial port in one of the planar side walls and two peripheral ports formed between the side walls and the guiding surfaces, a reversible rotary drive means connected to said impeller whereby the axial port becomes the inlet in one direction of rotation and the peripheral ports become the inlet in the reverse direction of rotation.

5. The pump motor combination of claim 4 in which the fluid impeller comprises a pair of planar side plates, each plate being a continuous surface composed of two semi-circular sections of equal radius which are arranged with the diametrical faces of the sections abutting, and the centers of rotation of the sections being offset from each other on either side of the center of rotation of the impeller whereby a portion of each diametrical face has a non-abutting portion.

6. The pump motor combination of claim 4 in which the axial port comprises a first shaft that extends outwardly from a first side wall of the impeller coaxial with the center of rotation of said impeller and has a central bore extending into the hollow interior of the impeller.

7. In combination with the fluid pump of claim 1 a reversible rotary drive means, said drive means being operatively connected to said impeller to drive the impeller selectively in either direction of rotation; the operative connection between the impeller and the drive means comprising in part a first cylindrical boss located on the outer surface of said casing coaxial with the axis of the enclosed cylindrical central cavity, a concentric bore in said boss extending from the outer end of the boss into the central cavity, an axially located impeller drive shaft extending outwardly from one side wall of the impeller, the impeller drive shaft extending into the concentric bore in said casing, and means for drivingly connecting the impeller drive shaft to the reversible drive means.

8. The fluid pump of claim 7 in which the means for connecting the impeller drive shaft to the reversible drive means includes a driven shaft having first and second ends thereof, said driven shaft being rotated at the first end by said drive means and being rotatably journalled adjacent the second end in the axial bore in the boss on the casing, outwardly of the impeller drive shaft, the impeller drive shaft having an axial bore extending inwardly from the outer end thereof, and the second end of the driven shaft extending into the bore in the outer end of the impeller drive shaft with means drivingly interconnecting the driven shaft and the impeller drive shaft.

9. The fluid pump of claim 1 in which radial lips encircle the peripheral ports to effect a wiping action in conjunction with the end walls of the casing cavity.

References Cited in the file of this patent UNITED STATES PATENTS 2,916,997 Terrie Dec. 15, 1959 3,040,663 Cushing June 26, 1962 FOREIGN PATENTS 475,781 France Mar. 25, 1915 531,372 France Oct. 21, 19211 $39,882 France July 1, 1922 843,638 France Apr. 3, 1939 

1. IN A FLUID PUMP, A STATIONARY CASING ENCLOSING A ROTARY IMPELLER; SAID CASING COMPRISING AN OUTER SURFACE AND AN ENCLOSED CYLINDRICAL CENTRAL CAVITY, SAID CAVITY BEING DEFINED BY PARALLEL, FLAT END WALLS INTERCONNECTED BY A CIRCULAR WALL SECTION HAVING ITS AXIS PERPENDICULAR TO SAID END WALLS; SAID IMPELLER HAVING AN AXIS OF ROTATION AND COMPRISING AN OUTER SURFACE AND A HOLLOW INTERIOR UNITARILY DEFINED BY A PAIR OF SPACED PARALLEL PLANAR SIDE WALLS INTERCONNECTED BETWEEN THEIR PERIPHERIES BY A PAIR OF GUIDING WALL SECTIONS PERPENDICULAR TO THE SIDE WALLS, EACH GUIDING WALL SECTION HAVING CONTIGUOUS, SEMICIRCULAR SURFACES AND STRAIGHT TERMINAL EDGES, SAID GUIDING WALL SECTIONS BEING OFFSET FROM EACH OTHER ON OPPOSITE SIDES OF THE AXIS OF ROTATION OF THE IMPELLER SO THAT ONE TERMINAL EDGE OF EACH GUIDING SURFACE IS FURTHER FROM THE AXIS OF ROTATION OF THE IMPELLER THAN THE OTHER TERMINAL EDGE OF THE SAME GUIDING SURFACE, SAID PLANAR SIDE WALLS AND TERMINAL EDGES DEFINING A PAIR OF PERIPHERAL PORTS; AN AXIAL PORT MEANS INTERCONNECTING THE HOLLOW INTERIOR OF SAID IMPELLER WITH THE OUTER SURFACE OF SAID CASING AND A TANGENTIAL PORT EXTENDING THROUGH SAID CASING TANGENT TO THE CIRCULAR WALL SECTION OF THE CAVITY AND INTERCONNECTING SAID CAVITY WITH THE OUTER SURFACE OF SAID CASING, SAID IMPELLER BEING DRIVINGLY JOURNALLED IN SAID CENTRAL CAVITY IN THE CASING WITH THE AXIS OF ROTATION OF THE IMPELLER BEING COAXIAL WITH THE AXIS OF THE CIRCULAR WALL SECTION OF THE CYLINDRICAL CAVITY; THE PLANAR SIDE WALLS OF SAID IMPELLER BEING PARALLEL TO THE END WALLS OF SAID CASING CAVITY AND ADJACENT THERETO; THE TERMINAL EDGE OF EACH GUIDING SURFACE, FURTHEST FROM THE AXIS OF ROTATION OF THE IMPELLER, IS ADJACENT THE CIRCULAR WALL SECTION OF SAID CASING CAVITY WHEREBY A SUBSTANTIAL AMOUNT OF FLUID MAY NOT PASS BETWEEN THE PLANAR SIDE WALLS OF SAID IMPELLER AND THE END WALLS OF SAID CASING CAVITY AND BETWEEN THE FURTHER TERMINAL EDGES OF THE GUIDING SURFACES OF SAID IMPELLER AND THE CIRCULAR WALL SECTION OF SAID CASING. 